EP3794647B1

EP3794647B1 - Method for producing light emitting diodes (leds) by one step film lamination

Info

Publication number: EP3794647B1
Application number: EP18918870.9A
Authority: EP
Inventors: Anna Ya Ching FENG; Lu Zou
Original assignee: Rohm and Haas Electronic Materials LLC; DDP Specialty Electronic Materials US 9 LLC
Current assignee: Rohm and Haas Electronic Materials LLC; DDP Specialty Electronic Materials US 9 LLC
Priority date: 2018-05-18
Filing date: 2018-05-18
Publication date: 2023-11-08
Anticipated expiration: 2038-05-18
Also published as: US11923483B2; CN112424957B; EP3794647A1; WO2019218336A1; TWI845507B; JP2021524057A; JP7362132B2; KR102449295B1; KR20210020877A; TW202003262A; US20210226100A1; CN112424957A

Description

TECHNICAL FIELD

The present invention relates to a method for producing dual color light emitting diodes (LEDs) and/or multi-color LEDs by one step film lamination.

TECHNICAL BACKGROUND

The following documents may be useful in understanding the background to the present disclosure: US 2013/221835 A1 which relates to a patterned lamination sheet incorporating an array of multiple light emitting devices, the sheet being formed by overlaying of components and one or more lamination steps; US 2018/057714 A1 which relates to curable silicone compositions which may contain a phosphor, and are suitable for sheet-forming for use in optical devices such as packaging of semiconductor chips to form an LED; and US 2016/230084 A1 which describes a condensation curable silicone composition containing particulates such as phosphors and including a nitrogen-containing base.
Dual color LEDs (or multi-color LEDs) are now more and more popular in smart phones like iPhones as Flash and outdoor lighting. In terms of application in Flash, there are generally two LEDs with different color (e.g., amber and white). By adjusting their ratio, the camera can adjust color of the flash to match what been determined to be the white balance of ambient light. Flash LED is an import application of colored phosphor films. Outdoor LED strip lamps with dual or more colors are also more and more popular in the market.
However, current methods for producing dual color LEDs generally comprise two steps: (1) making two different color LEDs separately, and (2) then assembling two different color LEDs together (see, Fig. 1, referred as old method 1). Another current method for producing dual color LED also comprises two steps: (1) adding a baffle between two LEDs, and (2) then dispensing two different silicone solutions with phosphor (see, Fig. 1, referred as old method 2). Currently, above two old methods are suffered with some deficiencies, such as low production efficiency (which requires two steps), low color quality (since phosphor particles tends to be settled in silicone solutions).
Accordingly, there is a need to provide a novel method for producing dual color LEDs and multi-color LEDs, which can produce high color quality dual/multiple color LEDs with high production efficiency.

SUMMARY

An objective of an exemplary embodiment of the present invention is to overcome the above and/or other deficiencies in the prior art. The inventors unexpectedly find that by controlling rheology performance (e.g., maximum tan δ, minimum G' and curing time) of the colored phosphor compositions, two or more LEDs can be laminated with two or more colored phosphor films by one step film lamination, such that it may produce high color quality dual or multiple color LEDs with high production efficiency.
In the present invention, by adjusting a ratio of a cure catalyst and silicone binder, or using a hydrosilylation curable organosiloxane composition, two or more colored phosphor compositions may have close rheology performance (e.g., maximum tan δ and gelling time).
Thus, the present invention provides a method for producing dual-color LEDs or multi-color LEDs as defined in claim 1, comprising: laminating two or more LEDs with two or more colored phosphor films by one step film lamination; wherein each of the colored phosphor film comprises each other different colored phosphor composition which has a Maximum tan δ; and the difference of each Maximum tan δ varies within a range of 0-30%.
In one embodiment of the present invention, each of the different colored phosphor composition has a gelling time, and the difference of each gelling time varies within a range of 0-50%.
In one embodiment of the present invention, the difference of each Maximum tan δ varies within a range of 0-15%.
In one embodiment of the present invention, the colored phosphor composition comprises a cure catalyst, a silicone binder and a phosphor; and the difference of gelling time and Maximum tan δ is controlled by adjusting a ratio of the catalyst and silicone binder, and/or a ratio of the silicone binder and phosphor.
In one embodiment of the present invention, the phosphor is pre-treated with a treatment agent, particularly when red or green phosphor is involved in phosphor film. In some embodiments, the treatment agent is identical to the cure catalyst as used. The pre-treatment method comprises: (1) contacting the phosphor with treatment agent for a period time so as to ensure a good dispersion of phosphor in the treatment agent; and (2) drying the phosphor coated with the treatment agent, which is ready to be used with the silicone binder.
In one embodiment of the present invention, the colored phosphor composition comprises a hydrosilylation curable organosiloxane composition and a phosphor.
Other features and aspects will become apparent from the following Detailed Description, the Drawings and the Claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention can be understood better in light of the description of exemplary embodiments of the present invention with reference to the accompanying drawings, in which:

FIG. 1 is a schematic diagram showing current methods for producing dual color LED (old methods 1 and 2) and an inventive method for producing dual color LEDs.
FIG. 2 is a diagram showing rheology profile of uncured silicone binder system in the present invention.
FIG. 3 is a schematic diagram showing an exemplary embodiment (Example 2) of the method for producing dual color LEDs in the present invention.
FIG. 4 is a schematic diagram showing an exemplary embodiment (Example 3) of the method for producing dual color LEDs in the present invention.

DETAILED DESCRIPTION

Hereafter, a detailed description will be given for preferred embodiments of the present disclosure.
In the present invention, the inventors find that by controlling rheology performance (e.g., maximum tan δ and gelling time) of the colored phosphor compositions, two or more LEDs are laminated with two or more colored phosphor films by one step film lamination. In one embodiment, two or more colored phosphor compositions may have close rheology performance (e.g., maximum tan δ and gelling time) by adjusting a ratio of a cure catalyst and silicone binder, and/or a ratio of the silicone binder and phosphor. In another embodiment, two or more colored phosphor compositions may have close rheology performance (e.g., maximum tan δ and gelling time) by using a hydrosilylation curable organosiloxane composition.
In the present invention, the method for producing LED comprises: laminating two or more LEDs with two or more colored phosphor films by one step film lamination; wherein each of the colored phosphor film comprises each respectively a different colored phosphor composition which has a Maximum tan δ; the difference of each Maximum tan δ varies within a range of 0-30%.
In one embodiment of the present invention, the difference of each Maximum tan δ varies within a range of 0-30%, 0-20%, 0-15%, 0-10%, 10-30%, 10-20%, 10-15%, 15-30%, 15-20%, or 20-30%.
The term, "the difference of each Maximum tan δ", as used herein, is represented by the following: $\begin{array}{l} the difference of each Maximum \tan δ \\ = \frac{(larger Maximum \tan δ - smaller Maximum \tan δ)}{smaller Maximum \tan δ} \times 100 % \end{array}$
In one embodiment of the present invention, each of the colored phosphor films comprises each respectively different colored phosphor composition which may have a gelling time; the difference of each gelling time varies within a range of 0-50%.
In one embodiment of the present invention, the difference of each gelling time varies within a range of 0-50%, 0-40%, 0-35%, 0-30%, 0-20%, 0-10%, 10-50%, 10-40%, 10-35%, 10-30%, 10-20%, 20-50%, 20-40%, 20-35%, 20-30%, 30-50%, 30-40%, 30-35%, 35-50%, 35-40%, or 40-50%.
The term, "the difference of each gelling time", as used herein, is represented by the following: $the difference of each gelling time = \frac{(larger gelling time - smaller gelling time)}{smaller gelling time} \times 100 %$
The term, "Maximum tan δ (or Max. tan δ)", as used herein, refers to maximum tan δ = loss modulus/storage modulus, which is used to characterize the silicone binder system's flowability capability at heating temperature. The term, "gelling time", as used herein is defined by time from Max. tan δ to tan δ=1, which is used to characterize how fast the silicone binder system cures. Said gelling time and Max. tan δ are most two important rheology performances for success phosphor one-step film lamination.
In general, uncured silicone binder system will flow first with temperature increase and then get cured. Figure 2 shows rheology profile of the uncured silicone binder system. In the present invention, said rheology profile is measured by rotational rheometer with the following conditions: (1) 25-150°C by 25 °C/min.; (2) 150°C for 30 min.; and (3) 0.1% distortion, 1.0Hz frequency, and by using 8 mm steel plate.
Since the curing performance of silicone binder system would be affected by various phosphor. For one step film lamination, two or more different colored phosphor composition should be tuned to provide close rheology performance (e.g., gelling time and maximum tan δ). In one embodiment of the present invention, the difference of each gelling time varies within a range of 0-50%, 0-40%, 0-35%, 0-30%, 0-20%, 0-10%, 10-50%, 10-40%, 10-35%, 10-30%, 10-20%, 20-50%, 20-40%, 20-35%, 20-30%, 30-50%, 30-40%, 30-35%, 35-50%, 35-40%, or 40-50%; and/or the difference of each Maximum tan δ varies within a range of 0-30%, 0-20%, 0-15%, 0-10%, 10-30%, 10-20%, 10-15%, 15-30%, 15-20%, or 20-30%. On the other hand, the more catalyst, the colored phosphor composition would cure fast. Thus, the present inventors unexpected find that the difference of gelling time and Maximum tan δ may be controlled by adjusting a ratio of the catalyst and silicone binder, and/or a ratio of the silicone binder and phosphor, so as to provide close rheology performance.
In one embodiment of the present invention, the colored phosphor composition comprises a cure catalyst, a silicone binder and a phosphor; and the difference of gelling time and Maximum tan δ is controlled by adjusting a ratio of the catalyst and silicone binder, and/or a ratio of the silicone binder and phosphor. In most embodiments, phosphors are add together with a silicone bonder and catalyst, and solvent such as toluene is add to adjust viscosity of the composition to around 2000-8000 mPa·s for easy film coating. After mixing, the slurry phosphor composition is coated on PET release liner by auto applicator. The wet phosphor film are then dry at room temperature for 5 min and then put in oven at a temperature of about 70°C for 30 min. The dried phosphor films are generally around 50-150 µm.
In the present invention, the cure catalyst may be selected from any catalyst known in the art to effect condensation cure of organosiloxanes, such as various tin or titanium catalysts. Curing catalyst can be any curing catalyst that may be used to promote condensation of silicon bonded hydroxy (=silanol) groups to form Si-O-Si linkages. Examples include, but are not limited to, amines and complexes of lead, tin, titanium, zinc, and iron. Other examples include, but are not limited to basic compounds, such as trimethylbenzylammonium hydroxide, tetramethylammonium hydroxide, n-hexylamine, tributylamine, diazabicycloundecene (DBU) and dicyandiamide; and metal-containing compounds such as tetraisopropyl titanate, tetrabutyl titanate, titanium acetylacetonate, aluminum triisobutoxide, aluminum triisopropoxide, zirconium tetra(acetylacetonato), zirconium tetrabutylate, cobalt octylate, cobalt acetylacetonato, iron acetylacetonato, tin acetylacetonato, dibutyltin octylate, dibutyltin laurate, zinc octylate, zinc bezoate, zinc p-tert-butylbenzoate, zinc laurate, zinc stearate, aluminium phosphate, and alminium triisopropoxide; organic titanium chelates such as aluminium trisacetylacetonate, aluminium bisethylacetoacetate monoacetylacetonate, diisopropoxybis(ethylacetoacetate)titanium, and diisopropoxybis(ethylacetoacetate)titanium. In some embodiments, the curing catalysts include zinc octylate, zinc benzoate, zinc p-tert- butylbenzoate, zinc laurate, zinc stearate, aluminium phosphate, and aluminum triisopropoxide. See, e.g. , U.S. Patent No. 8,193,269 . Other examples of curing catalysts include, but are not limited to aluminum alkoxides, antimony alkoxides, barium alkoxides, boron alkoxides, calcium alkoxides, cerium alkoxides, erbium alkoxides, gallium alkoxides, silicon alkoxides, germanium alkoxides, hafnium alkoxides, indium alkoxides, iron alkoxides, lanthanum alkoxides, magnesium alkoxides, neodymium alkoxides, samarium alkoxides, strontium alkoxides, tantalum alkoxides, titanium alkoxides, tin alkoxides, vanadium alkoxide oxides, yttrium alkoxides, zinc alkoxides, zirconium alkoxides, titanium or zirconium compounds, especially titanium and zirconium alkoxides, and chelates and oligo- and polycondensates of the above alkoxides, dialkyltin diacetate, tin(II) octoate, dialkyltin diacrylate, dialkyltin oxide and double metal alkoxides. Double metal alkoxides are alkoxides containing two different metals in a particular ratio. In some embodiments, the curing catalysts include titanium tetraethylate, titanium tetrapropylate, titanium tetraisopropylate, titanium tetrabutylate, titanium tetraisooctylate, titanium isopropylate tristearoylate, titanium truisopropylate stearoylate, titanium diisopropylate distearoylate, zirconium tetrapropylate, zirconium tetraisopropylate, zirconium tetrabutylate. See, e.g., U.S. Patent No. 7,005,460 . In addition, the curing catalysts include titanates, zirconates and hafnates as described in DE 4427528 C2 and EP 0 639 622 B1 . In some embodiments, the curing catalyst comprises Dow Corning^® LF-9000 Film Encapsulant Catalyst (commercially available from DOW CORNING CORPORATION).
In the present invention, treatment agent is used when handling specific phosphors like red one and etc. Treatment agent is similar with catalyst in effective composition while it is around 2-10 times higher concentration.
In the present invention, the silicone binder may be selected from any silicone binder known in the art to form organosiloxane copolymer. In some embodiments, the silicone binder may be solved in an organic solvent. Also, the silicone binder may be those as described in WO 2013/134018 . In some embodiments, the silicone binder comprises Dow Corning^® LF-1020 (commercially available from DOW CORNING CORPORATION).
In the present invention, the phosphor may be selected from any phosphor known in the art. Examples thereof include, but are not limited to, YAG-04 phosphor (commercially available from Intematix Corporation), NYAG4454-L phosphor (commercially available from Intematix Corporation), BR-102L Phosphor (commercially available from Mitsubishi Chemical Corporation), GAL 550 Phosphor (commercially available from Intematix Corporation) or any combinations thereof.
In one embodiment of the present invention, the phosphor may be pre-treated with a treatment agent, particularly when red or green phosphor is involved in phosphor film. In some embodiments, the treatment agent is preferably a basic compounds, such as trimethylbenzylammonium hydroxide, tetramethylammonium hydroxide, n-hexylamine, tributylamine, diazabicycloundecene (DBU) and dicyandiamide. The pre-treatment method comprises: (1) contacting the phosphor with treatment agent for a period time so as to ensure a good dispersion of phosphor in the treatment agent; and (2) drying the phosphor coated with the treatment agent, which is ready to be used with the silicone binder. Phosphor pre-treatment is one way to lower down the impact of phosphor on silicone binder cure performance.
For example, the pre-treatment method comprises:

Weighing a phosphor and a treating agent in a ratio of 1:1;
Charging the phosphor and a treating agent in a closed sealed container;
mixing and soaking the phosphor in the treating agent for 4 hours, so as to ensure a good dispersion of phosphor in the treatment agent solution;
Filtering out the phosphor or using other method to separate phosphor from the treating agent; and
Putting the wet phosphor into a drying oven and heating up to 150°C for 8 hours, so as to provide dried phosphor which is ready to be used for formulations.

In one embodiment of the present invention, the colored phosphor composition comprises a hydrosilylation curable organosiloxane composition and a phosphor. The hydrosilylation curable organosiloxane composition may comprise a hydrosilylation catalyst. In some embodiments, the hydrosilylation curable organosiloxane composition comprises Dow Corning^® LF-1112 Phosphor Film Binder A&B Kit (commercially available from DOW CORNING CORPORATION). Also, the hydrosilylation curable organosiloxane composition may be those as described in WO 2016/022332A1 .
In the present invention, the method for producing a LED may greatly improve production efficiency (i.e., dual and multi-color LEDs in one step) and lower cost of ownership. Further, it may improve uniformity of phosphor dispersion, thereby improve color quality of LEDs.
Ranges can be expressed herein as from "about" one particular value, and/or to "about" another particular value. When such a range is expressed, examples include from the one particular value and/or to the other particular value. Similarly, when values are expressed as approximations, by use of the antecedent "about," it will be understood that the particular value forms another aspect. It will be further understood that the endpoints of each of the ranges are significant both in relation to the other endpoint, and independently of the other endpoint.
Unless otherwise expressly stated, it is in no way intended that any method set forth herein be construed as requiring that its steps be performed in a specific order. Accordingly, where a method claim does not actually recite an order to be followed by its steps or it is not otherwise specifically stated in the claims or descriptions that the steps are to be limited to a specific order, it is no way intended that any particular order be inferred.

Reference Example 1: Preparation of YAG-04 phosphor film

The materials as used in Reference Example 1 are as follows:

Silicone binder 1: Dow Corning^® LF-1020 Phosphor Film Binder, 5g, commercially available from DOW CORNING CORPORATION;
Catalyst 1: Dow Corning^® LF-9000 Film Encapsulant Catalyst, 0.075g, commercially available from DOW CORNING CORPORATION; and
Phosphor 1: YAG-04 phosphor, 5g, commercially available from Intematix Corporation.

In Reference Example 1, the ratios of Silicone binder 1 to Catalyst 1 are 100: 1, 100:1.5 and 100: 2, respectively. And the ratio of Silicone binder 1 to Phosphor 1 is 100:100.
Sample preparation (taking a ratio of Silicone binder 1 to Catalyst 1=100:1.5 as example)

(1) providing 5g Phosphor 1 with 5g Silicone binder 1 and 0.075g Catalyst 1, with adding 0.3g toluene as organic solvent to adjust the viscosity, and mixing in a ThinkyARV-310 planetary vacuum mixer to provide a mixed slurry;
(2) using Hohsen auto applicator, coating the mixed slurry on a PET release liner;
(3) drying the PET release liner at room temperature for 5 min. and then put it into a drying oven at a temperature of 70°C for 30 min., resulting in a dry film with a thickness of 75 µm.

Test procedure

The rheology performance is measured by TA ARES G2 rheometer using following conditions: (1) 15-150°C by 25 °C/min.; (2) 150°C for 30 min.; and (3) 0.5% strain, 1.0Hz frequency, and by using 8 mm steel plate.

Silicone Binder 1 : Catalyst 1 Gelling time (sec.) Max. tan δ

100 : 1 1224 2.21

100 : 1.5 510 1.79

100 : 2 315 1.25

Reference Example 2: Preparation of NYAG4454-L phosphor film

The materials as used in Reference Example 2 are as follows:

Silicone binder 1: Dow Corning^® LF-1020 Phosphor Film Binder, 5g, commercially available from DOW CORNING CORPORATION;
Catalyst 1: Dow Corning^® LF-9000 Film Encapsulant Catalyst, 0.1g, commercially available from DOW CORNING CORPORATION; and
Phosphor 2: NYAG4454-L phosphor, 5g, commercially available from Intematix Corporation.

In Reference Example 2, the ratios of Silicone binder 1 to Catalyst 1 are 100: 2, 100:2.5 and 100: 3, respectively. And the ratio of Silicone binder 1 to Phosphor 2 is 100:100.
Sample preparation (taking a ratio of Silicone binder 1 to Catalyst 1=100:2 as example)

(1) providing 5g Phosphor 2 with 5g Silicone binder 1 and 0.1g Catalyst 1, with adding 0.3g toluene as organic solvent to adjust the viscosity, and mixing in a ThinkyARV-310 planetary vacuum mixer to provide a mixed slurry;
(2) using Hohsen auto applicator, coating the mixed slurry on a PET release liner;
(3) drying the PET release liner at room temperature for 5 min. and then put it into a drying oven at a temperature of 70°C for 30 min., resulting in a dry film with a thickness of 75 µm.

Test procedure

The rheology performance is measured by TA ARES G2 rheometer using following conditions: (1) 15-150°C by 25 °C/min.; (2) 150°C for 30 min.; and (3) 0.5% strain, 1.0Hz frequency, and by using 8 mm steel plate.

Silicone Binder 1 : Catalyst 1 Gelling time (sec.) Max. tan δ

100 : 2 515 1.84

100 : 2.5 356 1.49

100 : 3 309 1.34

Example 1: One step film lamination

From above Reference Examples 1 and 2, it could be noted that for close rheology performance, the ratio of Silicone binder 1 to Catalyst 1 for NYAG4454-L phosphor should be decreased to 100:2 in comparison with said "100:1.5" for YAG-04 phosphor. The difference of the gelling time varies within 1%; and the difference of each Maximum tan δ varies within 2.8%.
The phosphor films as obtained in Reference Examples 1 and 2 are laminated by Fulin PLC-100A vacuum laminator. The lamination conditions are as follows:

Lamination temperature: 124.6°C ;
Lamination time: 300 seconds; and
Vacuum: 0.34 kPa

In this example, two different colored phosphor films are successfully laminated on LEDs in one step film lamination, which exhibits uniform phosphor dispersion and better color quality.

Example 2: red phosphor pre-treatment and dual color phosphor film lamination.

2.1 Cold white phosphor film 3C formulation:

The materials as used are as follows:

Silicone binder 1: Dow Corning^® LF-1020 Phosphor Film Binder, 5g, commercially available from DOW CORNING CORPORATION;
Catalyst 1: Dow Corning^® LF-9000 Film Encapsulant Catalyst, 0.075g, commercially available from DOW CORNING CORPORATION; and
Phosphor 1: YAG-04 Phosphor, commercially available from Intematix Corporation.
Phosphor 3: BR-102L Phosphor, commercially available from Mitsubishi Chemical Corporation.

In 3C formulation, the ratio of Silicone binder 1 to Catalyst 1 is 100:1.5. And the ratio of Silicone binder 1 to Phosphors 1 and 3 is 100:56. The ratio of Phosphor 1 to Phosphor 3 is 40:1. BR-102L is pretreated with treatment agent following below procedure:

Weighing the phosphor 3 and the treating agent in a ratio of 1:1.
Charging them in an appropriate container and closely tight it.
Using mixer to soak the phosphor in the treating agent for 4 hours and ensure a good dispersion of phosphor in the solution.
Filtering out the phosphor to separate phosphor from the treating agent.
Putting the wet phosphor into a drying oven and heating up to 150°C for 8 hours.
The dried phosphor is ready to be used for formulations.

Sample preparation

(1) providing 2.732g Phosphor 1 and 0.068g Phosphor 3 with 5g Silicone binder 1 and 0.075g Catalyst 1, with adding 0.3g toluene as organic solvent to adjust the viscosity, and mixing in a ThinkyARV-310 planetary vacuum mixer to provide a mixed slurry;
(2) using Hohsen auto applicator, coating the mixed slurry on a PET release liner;
(3) drying the PET release liner at room temperature for 5 min. and then put it into a drying oven at a temperature of 70°C for 30 min., resulting in a dry film with a thickness of 80 µm.

Test procedure

The rheology performance is measured by TA ARES G2 rheometer using following conditions: (1) 15-150°C by 25 °C/min.; (2) 150°C for 20 min.; and (3) 0.5% strain, 1.0Hz frequency, and by using 8 mm steel plate.

2.2 Warm white phosphor film 3W formulation:

The materials as used are as follows:

Silicone binder 1: Dow Corning^® LF-1020 Phosphor Film Binder, 5g, commercially available from DOW CORNING CORPORATION;
Catalyst 1: Dow Corning^® LF-9000 Film Encapsulant Catalyst, 0.050g, commercially available from DOW CORNING CORPORATION; and
Phosphor 1: YAG-04 Phosphor, commercially available from Intematix Corporation.
Phosphor 3: BR-102L Phosphor, commercially available from Mitsubishi Chemical Corporation.

In 3W formulation, the ratio of Silicone binder 1 to Catalyst 1 is 100:1. And the ratio of Silicone bonder 1 to Phosphors 1 and 3 is 100:139. The ratio of Phosphor 1 to Phosphor 3 is 2:1. BR-102L is pretreated with treatment agent following above similar procedure.

Sample preparation

(1) providing 4.633g Phosphor 1 and 2.317g Phosphor 3 with 5g Silicone binder 1 and 0.050g Catalyst 1, with adding 0.5g toluene as organic solvent to adjust the viscosity, and mixing in a ThinkyARV-310 planetary vacuum mixer to provide a mixed slurry;
(2) using Hohsen auto applicator, coating the mixed slurry on a PET release liner;
(3) drying the PET release liner at room temperature for 5 min. and then put it into a drying oven at a temperature of 70°C for 30 min., resulting in a dry film with a thickness of 86 µm.

Test procedure

The rheology performance is measured by TA ARES G2 rheometer using following conditions: (1) 15-150°C by 25 °C/min.; (2) 150°C for 20min.; and (3) 0.5% strain, 1.0Hz frequency, and by using 8 mm steel plate.

2.3 Rheology performance

Cold white and warm white phosphor films' rheology performances are listed in below table.

Phosphor film Gelling time (sec.) Max. tan δ

3C 526 1.36

3W 360 1.48

2.4 Lamination:

Cold white and warm white phosphor films 3C and 3W are laminated by Fulin PLC-100A vacuum laminator. Detailed lamination condition:

Lamination temperature: 124.6°C;
Lamination time: 300 seconds; and
Vacuum: 0.34 kPa

As shown in Fig. 3, Cold white and warm white phosphor films 3C and 3W are successfully laminated on LEDs in one step film lamination, which exhibits uniform phosphor dispersion and better color quality.

Example 3: hydrosilylation cure dual color phosphor film preparation and lamination.

3.1 Cold white phosphor film 4C formulation:

The materials as used are as follows:

Silicone binder 4: Dow Corning^® LF-1112 Phosphor Film Binder Part A + Part B (1:1), 5g, commercially available from DOW CORNING CORPORATION;
Phosphor 1: YAG-04 Phosphor, commercially available from Intematix Corporation..
Phosphor 4 : GAL550 Phosphor, commercially available from Intematix Corporation..
In 4C formulation, the ratio of Silicone binder 4 to Phosphors 1 and 4 is 100:27. The ratio of Phosphor 1 to Phosphor 4 is 5:1.

Sample preparation

(1) providing 1.125g Phosphor 1 and 0.225g Phosphor 4 with 2.5g part A of Silicone binder 4 and 2.5g part B of Silicone binder 4, with adding 0.3g propyl propionate as organic solvent to adjust the viscosity, and mixing in a ThinkyARV-310 planetary vacuum mixer to provide a mixed slurry;
(2) using Hohsen auto applicator, coating the mixed slurry on a PET release liner;
(3) drying the PET release liner at room temperature for 5 min. and then put it into a drying oven at a temperature of 70°C for 30 min., resulting in a dry film with a thickness of 52 µm.

Test procedure

The rheology performance is measured by TA ARES G2 rheometer using following conditions: (1) 15-125°C by 20 °C/min.; (2) 125°C for 30min.; and (3) 0.5% strain, 1.0Hz frequency, and by using 8 mm steel plate.

3.2 Warm white phosphor film 4W formulation:

The materials as used are as follows:

Silicone binder 4: Dow Corning^® LF-1112 Phosphor Film Binder Part A + Part B (1:1), 5g, commercially available from DOW CORNING CORPORATION;
Phosphor 1: YAG-04 Phosphor, commercially available from Intematix Corporation.
Phosphor 5: MPR-1003 Phosphor, commercially available from Mitsubishi Chemical Corporation.

In 4W formulation, the ratio of Silicone binder 4 to Phosphors 1 and 5 is 100:110. The ratio of Phosphor 1 to Phosphor 5 is 10:1.

Sample preparation

(1) providing 5g Phosphor 1 and 0.5g Phosphor 5 with 2.5g part A of Silicone binder 4 and 2.5g part B of Silicone binder 4, with adding 0.5g propyl propionate as organic solvent to adjust the viscosity, and mixing in a ThinkyARV-310 planetary vacuum mixer to provide a mixed slurry;
(2) using Hohsen auto applicator, coating the mixed slurry on a PET release liner;
(3) drying the PET release liner at room temperature for 5 min. and then put it into a drying oven at a temperature of 70°C for 30 min., resulting in a dry film with a thickness of 86 µm.

Test procedure

Rheology performance

Cold white and warm white phosphor films' rheology performances are listed in below table.

Phosphor film Gelling time (sec.) Max. tan δ

4C 386 1.70

4W 280 1.49
As shown in Example 3, in cased of a hydrosilylation curable composition, phosphor will not impact silicone binder system's Rheology performance, thereby curing performance. So it not necessary to adjust the mix ratio of silicone binder to phosphor.

Lamination:

Cold white and warm white phosphor films 4C and 4W are laminated by Fulin PLC-100A vacuum laminator. The lamination conditions are as follows:

Lamination temperature: 121.8°C;
Lamination time: 300 seconds; and
Vacuum: 0.34 kPa

As shown in Fig. 4, Cold white and warm white phosphor films 4C and 4W are successfully laminated on LEDs in one step film lamination, which exhibits uniform phosphor dispersion and better color quality.
The above descriptions are merely embodiments of the invention and are not intended to restrict the scope of the invention, which is defined by the scope of the appended claims.

Claims

A method for producing dual-color LEDs and/or multi-color LEDs by lamination of LEDs with colored phosphor film, comprising:
laminating two or more LEDs with two or more colored phosphor films by one step film lamination thereby producing dual and/or multi-color LEDs from two or more LEDs and two or more colored phosphor films in one step;

wherein each of the colored phosphor films comprises each respectively a different colored phosphor composition which has a Maximum tan δ; and

the difference of each Maximum tan δ varies within a range of 0-30%,

each colored phosphor composition comprising a silicone binder.
The method according to claim 1, wherein each of the different colored phosphor composition has a gelling time, and the difference of each gelling time varies within a range of 0-50%.
The method according to claim 1, wherein the difference of each Maximum tan δ varies within a range of 0-15%.
The method according to claim 1, wherein the colored phosphor composition comprises a cure catalyst, and a phosphor; and
the difference of Maximum tan δ is controlled by adjusting a ratio of the catalyst and silicone binder, and/or a ratio of the silicone binder and phosphor.
The method according to claim 2, wherein the colored phosphor composition comprises a cure catalyst, and a phosphor; and
the difference of gelling time and/or Maximum tan δ is controlled by adjusting a ratio of the catalyst and silicone binder, and/or a ratio of the silicone binder and phosphor.
The method according to claim 4 or 5, wherein the phosphor is pre-treated with a treatment agent.
The method according to claim 6, wherein the treatment agent is a basic compound.
The method according to claim 6, wherein the phosphor is pre-treated by the following method: (1) contacting the phosphor with treatment agent for a period time so as to ensure a good dispersion of phosphor in the treatment agent; and (2) drying the phosphor coated with the treatment agent, which is ready to be used with the silicone binder.